.TH RA_BMP 1 3/25/04 RADIANCE
.SH NAME
ra_bmp - convert RADIANCE picture to/from Windows BMP image
.SH SYNOPSIS
.B ra_bmp
[
.B \-b
][
.B "\-g gamma"
][
.B "\-e spec"
][
.B "-p xr yr xg yg xb yb xw yw"
]
[
[
.B input|-
[
.B output
]
]
.br
.B ra_bmp
.B \-r
[
.B "\-g gamma"
][
.B "\-e +/-stops"
]
[
[
.B input|-
[
.B output
]
]
.SH DESCRIPTION
.I Ra_bmp
converts between RADIANCE and a Windows BMP image.
During forward conversion, the
.I \-b
option produces 8-bit grayscale output rather than 24-bit RGB.
The
.I \-g
option specifies the exponent used in monitor gamma correction;
the default value is 2.2.
The
.I \-e
option specifies a tone-mapping method or exposure compensation.
If the argument is one of the special words "auto", "human", or "linear",
the image will be tone-mapped with histogram adjustment,
human vision simulation, or an averaged linear exposure,
respectively.
(These words may be abbreviated by one or more letters.)\0
Otherwise, the exposure specification is interpreted as a
linear compensation value in integer f-stops, which must
be proceeded by a '+' or '-'.
The CRT color output primaries may be specified with the
.I \-p
option.
.PP
The
.I \-r
option invokes a reverse conversion, from a Windows BMP image
to a RADIANCE picture.
Tone-mapping and monitor primaries are not
supported for reverse conversion.
.PP
.I Ra_bmp
can accept 16-bit or color-mapped BMP files on input,
but cannot not produce them on output.
.PP
A hyphen ('-') may be specified to indicate standard input for
either forward or reverse conversion so that an output file may be
specified.
If the BMP input is taken from the standard input or sent to the
standard output without tone-mapping, then the scanlines may
be reversed from their usual ordering.
Reversed scanlines sometimes causes difficulties for programs attempting
to interpret the resulting RADIANCE picture or BMP image, which
may be rejected or displayed inverted.
.SH AUTHOR
Greg Ward
.SH "SEE ALSO"
pfilt(1), ra_ppm(1), ra_pr(1), ra_pr24(1), ra_t8(1), ra_t16(1),
ra_tiff(1), ximage(1)
